Cover clamp



June 13, 1939. A, D. FORBES COVER CLAMP Filed Sept. 23, 1937 INVENTOR A [/4217 DForbes. v

WITNESES:

Patented June 13, 1939 UNITED STATES PATENT OFFICE COVER CLAMP sylvania Application September 23, 1937, Serial No. 165,267

2 Claims.

This invention relates to cover clamps for cases and, in particular, to the clamps for securing covers on the cases for electrical apparatus.

In electrical apparatus and particularly transformers, which contain an insulating and cooling medium, it is desirable that the covers of the casings be held securely and tightly in place during normal operation of the enclosed electrical apparatus in order to protect the apparatus from dirt and moisture. It is also desirable that the cover securing means be so constructed as to be quickly and readily released for removing the cover when repairs are necessary or it is desired to inspect the apparatus.

An object of this invention is to provide an improved cover clamp which will securely and tightly hold the cover on the case, but may quickly and readily be released to permit the cover to be removed from the case.

Another object of this invention is to provide a cover clamp which, when tightened into engagement with the cover of a case, will be biased toward the center of the case thereby securely holding the cover in position on the case.

Other objects of this invention will become apparent from the following description, when taken in conjunction with the accompanying drawing, in which:

Figure 1 is a plan view of the cover of a transformer illustrating the positioning of the cover clamp embodied in this invention;

Fig. 2 is an elevational view, partly in section, of the upper part of the transformer case employing the cover clamp of this invention;

Fig. 3 is a view of a fragment of the casewith the cover clamp and the cover disengaged to permit the cover to be removed.

Fig. 4 is a view in elevation of the lifting hook associated with the case.

Fig. 5 is a top plan view of the lifting-hook illustrated in Fig. 4.

Fig. 6 is a view, in elevation, of the holding member associated with the lifting hook.

Fig. 7 is a top plan View of the holding member illustrated in Fig. 6; and,

Fig. 8 is an exploded view, in perspective, of the cover clamp assembly embodying the teachings of thisinvention.

Referring tothe drawing and in particular to Figs. 1 and 2 thereof, this invention is illustrated as applied to a transformer case 'lB which is provided with a cover l2 fitted over the upper rolled edge M of the side wall of the case. The cover carries a pair of bushings l6 for insulating the high voltage leads from the coils (not shown) of the transformer and is also provided-with the conventional manhole cover IS. The low voltage leads (not shown) may be carried through any suitable bushings disposed in the case as desired.

In order to tightly hold the cover 12 in position on the case, a plurality of cover clamps 20 may be disposed in spaced relation about the case, as desired. As illustrated in Fig. l, the cover I2 is maintained in position by three of the equally spaced cover clamps 20, although, as will be understood, any number of cover clamps may be employed depending upon the size of the case and the cover.

As illustrated, each cover clamp '20 comprises a plurality of elements including a lifting hook 22 welded or otherwise secured to the outer face of the side wall of the case It adjacent its upper rolled edge, a holding member 24 and a bolt 26 having a nut 28 associated therewith, as will be described more fully hereinafter.

The lifting hook 22 may be fabricated from a single sheet of suitable metal which is so cut, stamped or punched to shape that it may be formed into the hollow lifting hook illustrated in Figs. 4, 5 and 8. As illustrated, the lower portion of the lifting hook is so fabricated as to form a hollow downwardly projecting pin 29 for cooperating with suitable hangers (not shown) for mounting on a pole or standard. The upper portion of the lifting hook is formed by the inwardly turned and spaced side walls 30 which terminate in the outwardly turned flanges 32, which serve as spaced feet for seating on the case wall.

In order to allow clearance for the cover [2 when the lifting hook is secured to the wall of the case adjacent its upper edge, a notch 34 of a size suitable for receiving the edge of the cover is carried in the upper edge of each of the side walls 30 of the lifting hook. A notch 36 is also provided in the lower edge of each of the spaced side walls 30 for receiving the head of the bolt 26, as will be explained more fully hereinafter.

The holding member'24 may also be fabricated from a single sheet of suitable metal which is so cut, stamped or punched to shape that it may be formed into the member illustrated in Figs. 6, 7 and 8. As illustrated, the holding member 24 is so fabricated with inwardly turned and spaced side 'walls 38, an end of which terminates in rounded or curved edges 40 to form a cover engaging portion for seating on the cover l2 of the case. The other end of the inwardly turned side walls extends downwardly to form a tail piece 42 for seating on the spacedside walls '30 of the lifting hook. The tail piece '42 also carriesa downwardly projecting lug 4-4 of a size suitable for fitting into the hollow space between the spaced'side walls '30 of the lifting hook, the purpose of which will be explained more fully hereinafter.

'In order to provide for receiving the bolt '26 for tightening the holding member 2 into engagement with the cover I2 when the holding member is seated on the lifting hook, a portion ,46 of the sheet metal blank forming the holding 60 member is bent over to seat on the upper edges of the spaced side walls 38. The portion 46 carries a suitable opening therein through which the bolt 26 may project and also functions as a seat for the nut 28 when the clamp assemblyis tightened to engage the cover.

In practice, with the lifting hook 22 seated on and secured to the side walls of the case I0 and the holding member 24 seated on the cover and the lifting hook as explained hereinbefore, the assembly may be tightened by screwing the nut 28 down on the bolt 26.

As illustrated in Fig. 2, the bolt 26 extends in a substantial vertical direction in the hollow space of the assembly, being inclined at a very slight angle from the vertical and having its bolt head disposed in the notches 36 in the lower edge of the side walls 30 of the lifting hook. In this position, with the tail piece 42 of the holding member seated on the lifting hook and the cover engaging portions 40 of the holding member seated on the cover l2, when the nut 28 is tightened on the bolt, a force is so applied to the holding member that the holding member is biased toward the center of the cover. This is because the substantially vertically extending bolt 26 projecting through the holding member between its cover engaging portion 4|] and the tail piece 42 exerts a pull on the holding member which, because of the length of the lever arm of the tail piece, tends to pivot the holding member in a counterclockwise direction about its seat on the lifting hook. Such a biasing force applied to the holding member causes the holding member to tightly clamp the cover in position on the case with its edge in the notches 34 of the lifting hook.

By providing the notches 36 in the lifting hook for receiving the head of the bolt 26, sufficient pressure or pull may be applied to the holding member 24 to cause it to tightly engage the cover l2. This is because the notches 36 are of such size as to prevent turning of the bolt 26 as the nut 28 is tightened thereon.

The lug 44 carried by the tail piece .2 of the holding member fits into the hollow space between the side walls 3!) of the lifting hook when the tail piece of the holding member seats on the lifting hook. In this position, the lug 44 tends to prevent sideways slippage of the holding member as it is forced into engagement with the cover and when sufficient force or pull is applied to the holding member, will abut the solid portion of the lifting hook joining the side walls 30 to prevent the holding member 24 from slipping off the lifting hook. Provision is thus made for negativing any tendency of the holding member to slip from its engagement with the cover as the assembly is tightened.

When it is desired to inspect or repair the apparatus within the case, the nut 28 may be so loosened as to permit the holding member to be so lifted from its engagement with the cover and with the lifting hook to withdraw the lug 44 from the hollow space between the side walls of the lifting hook. The holding member may then be turned through a angle and brought to rest on the lifting hook as illustrated in Fig. 3 free from the cover. The cover may then be removed. In this position, the assembly is intact with the bolt loosely held in position between the side walls of the lifting hook by the holding member, whereby when it is desired to again tighten the cover on the case, the holding member may be lifted into the position where it seats on the lifting hook with the lug 44 disposed between the side walls of the lifting hook, and the assembly can again be tightened.

7 Although this invention has been described with reference to a particular embodiment thereof, it is, of course, not to be limited thereto except insofar as is necessitated by the prior art and the scope of the appended claims.

I claim as my invention:

1. A clamp assembly for securing a cover on a case comprising, a hollow lifting hook having spaced side walls terminating in spaced feet for seating on the case, means for securing the lifting hook to the case, a holding member for engaging the cover associated with the lifting hook, the holding member carrying a tail piece for seating on the upper edges of the side walls of the lifting hook when it engages the cover, a lug carried by the tail piece projecting downwardly between the side walls and cooperating with the lifting hook to limit the extent of movement of the holding member when engaging the cover, the lower edge of each of the side walls of the lifting hook having a notch disposed therein, and means comprising a bolt and associated nut disposed in a substantially vertical position between the side walls of the lifting hook and projecting through the holding member between the cover engaging portion and the tail piece thereof for cooperating with the lifting hook and the holding member to insure a tight engagement of the holding member with the cover, a bolt head of the bolt seating in the notches in the lower edges of the lifting hook to prevent rotation of the bolt when holding the holding member and the cover in tight engagement.

2. A clamp assembly for securing a cover on a case comprising, a hollow lifting hook having spaced'side walls terminating in spaced feet for seating on the case, means for securing the lifting hook to the case, a holding member for engaging the cover associated with the lifting hook, the holding member carrying a tail piece for seating on the upper edges of the side walls of the lifting hook when it engages the cover, a lug carried by the tail piece projecting downwardly between the side walls and cooperating with the lifting hook to permit the extent of movement of the holding member when engaging the cover, the lower edge of each of the side walls of the lifting hook having a notch disposed therein, and means comprising a bolt and associated nut disposed in a substantially vertical position between the side walls of the lifting hook and projecting through the holding member between the cover engaging portion and the tail piece thereof for cooperating with the lifting hook and the holding member to insure a tight engagement of the holding member with the cover, the'bolt head of the bolt seating in the notches in the lower edges of the lifting hook to prevent rotation of the bolt when holding the holding member and the cover in tight engagement, the nut associated with the bolt being disposed for movement to permit the holding member to disengage the cover and to be lifted from its seat on the lifting hook and so turned that its tail piece and the lug carried thereby clears the space between the side walls of the lifting hook whereby it may be dropped to rest on the lifting hook free from the cover.

ALLAN D. FORBES. 

